Forum Discussion

troester80's avatar
troester80
Explorer
Jan 14, 2015

closing toilet hole in black holding tank

So I am in the middle of a travel trailer gut job and have decided to go with a dry flush toilet. I am wondering the best way to close the current toilet hole in the black holding tank. I am thinking at some point in the future to use it as an overflow tank for grey water, so I don't want to remove it but do want it to be patched/ closed off properly without spending a ton of money. Any diy ideas would be great!

7 Replies

Sort By
  • jplante4's avatar
    jplante4
    Explorer II
    Jan 15, 2015
    mdamerell wrote:
    How to NOT Install a Composting Toilet

    Is this what you are thinking? He just installed a extendable plug to seal the black tank and put a false floor over it for his composting toilet.


    You should really post a "Gone with the Wynns" warning when you post a link to their videos. :E
  • time2roll's avatar
    time2roll
    Nomad
    Jan 15, 2015
    Plasti-mend can easily make a permanent repair to close the opening.
    Basically you glue on a sheet of ABS over the hole.

    OK I assume the tank is black ABS.

    If you have polyethylene (usually white) then you need to have it plastic welded or a screw on plate cover.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Jan 15, 2015
    Are you talking about closing up floor flange (leaving it in place closed off)

    OR

    Removal of toilet to tank line and closing off hole in top of tank?

    Either of the above for floor flange.

    But it you are talking about hole in top of tank.......cut line off and glue end cap on it or glue a threaded fitting on the line and screw plug in it.
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Jan 15, 2015
    Most flanges will be screwed in to a 3" NPT fitting- a 3" plug would let you remove the floor flange.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,239 PostsLatest Activity: Apr 25, 2025